Solar cells are devices for converting solar radiation into electrical energy. If a large reverse bias occurs in a solar cell, substantial power dissipation in the solar cell can result in heated areas known as hotspots. Hotspots can have a variety of causes. For example, when shaded or soiled, solar cells can be forced into reverse bias and experience local heating unless a bypass diode is turned on. Hotspots can also occur due to defects (e.g., PMOS defects) in a solar cell.
Hotspot testing is a method for testing solar cells. For example, hotspot testing can determine whether solar cells have a pre-determined voltage in reverse bias such that the cells remain at a sufficiently low temperature and do not become hotspots in the field.